I would add that you should practice braking hard a few times when you first start out. This will get the passanger aware of what it may feel like and it will let you feel and prepare for where they will be pushing/leaning into you in that situation.
I don't know where you are going in AZ, but be aware that in sharp twisties that are going up or down hill, the bike will handle VERY differently with a larger passenger on the back. Uphill the front tire will fell like it lifts much more when you load the suspension/twist the throttle. Descents will compress the front much more. The ride to Tortilla Flat or over the mountains into Jerome will really let you experince this. My wife was very uncomfortable with this the first time given the sharp turns and height of the cliffs. If you passanger is afraind of heights or claustrophobic you may want to think of that when you plan your route. What you may think if a beautiful, narrow canyon, could be a panic attack for your passanger.
I prefer my passangers to sit comfortably and pretend they are luggage. No leaning/helping me turn. It is not so bad if they do this in long, sweeping turns, but in a sharp turn it will really through you off the mark.
Please check your belt tension before and especially after. Two up can really stretch the belt.
Be aware of the passenger foot pegs. If you are not used to them being down they may hit you in the back of the calves as you come to a stop or go to take off. Also, if your passenger has larger feet, this will make this worse.
Finally, since they are typically looking left, right or at the back of your head, they do not see the road ahead. A bump or dip can upset a passanger and make them grab tight or panic. One of my instructions is that I will tap their leg/knee with my hand. This means to prepare for something: bump, mild swerve, etc. You can do this very quickly.